import  numpy as np
# arange 将0-50每隔10个分成一份，
# reshape 将一维数组分层6行1列的二维数组
a = np.arange(0,51,10).reshape(6,1)+ np.arange(6)
print(f'a = {a}')

print(a[3,2])  #32
print(a[2,-1]) # 25

print(a[0,2:                                                                                                                                                                                                                                                                                                                                                       v5]) #2,3,4